The present invention relates generally to a communication control apparatus preferably for use in a network such as a LAN (Local Area Network). More particularly, the present invention relates to a communication control apparatus that stores, for each of node apparatuses connected to the network, information representative of synchronization signal transmission and reception capabilities and synchronization signal transmission/reception setting status, and sets master and slaves of the synchronization signal appropriately and simply with reference to pieces of the stored information.
Systems for connecting plural music performance apparatuses (such as a synthesizer, a rhythm machine, a sequencer, and a computer) for synchronous performance are known in which MIDI (Musical Instrument Digital Interface) compliant apparatuses are interconnected by a MIDI cable to transmit a MIDI clock consisting of an 8-bit message of hexadecimal xe2x80x9cFBxe2x80x9d from one MIDI apparatus on the data transmission side to another MIDI apparatus on the data reception side, thereby performing music while taking synchronization based on this synchronization signal.
However the above-mentioned prior-art MIDI performance systems have a data transfer rate as low as 31.25 Kpbs, being incapable of constructing a system in which music is performed while transmitting sample data by use of a sampler having a sampling clock of 44.1 KHz.
A music performance system capable of providing high-speed data transfer may be constructed by use of a high-speed interface (having data transfer rates up to 10 through 50 Mbps) such as USB (Universal Serial Bus) or IEEE 1394. Currently, however, no sufficient researches have been carried out into the setting of master/slave for the synchronization information transmission/reception in such high-speed networks. As with the conventional MIDI scheme, it could be possible to adopt a scheme in which the synchronization information is always transmitted from an upstream of data to a downstream. However, such a rigid scheme causes the flow of the synchronization information to be restricted by the flow of music data, thereby making it impossible to provide proper settings of the master and slaves. It is also difficult with such a rigid scheme for users to execute master/slave setting by referring to instruction manuals and like.
It is therefore an object of the present invention to provide a novel communication control apparatus, which permits the proper and simple setting of transmission/reception nodes (master/slaves) of synchronization information in a high-speed network.
In carrying out the invention and according to one aspect thereof, there is provided a first communication control apparatus for setting a plurality of node apparatuses involved in a network to either of a transmitter and a receiver of synchronization information circulated through the network to synchronize the node apparatuses with each other. In the communication control apparatus, a storage device memorizes capability information representing either of an active capability to transmit the synchronization information and a passive capability to receive the synchronization information, owned by each of the node apparatuses. An indicating device indicates the active capabilities and the passive capabilities owned by the node apparatuses involved in the network according to the memorized capability information. A specifying device is operated in association with the indicated active capabilities and the passive capabilities of the node apparatuses for outputting status information effective to specify each node apparatus to a transmitter or a receiver of the synchronization information. A plurality of memory blocks are provided in correspondence to the plurality of the node apparatuses to memorize status information of the corresponding node apparatuses. A registering device registers each of the outputted status information into each memory block to set the corresponding node apparatus to a transmitter of the synchronization information when the status information specifies the transmitter, and to set the corresponding node apparatus to a receiver of the synchronization information when the status information specifies the receiver.
According to the first communication apparatus, the indicating device indicates the capability of transmission or reception on the basis of the synchronization capability information stored in the storage device for each of the plurality of node apparatuses. The user refers to the indication made by the indicating device and specifies the transmission or the reception of synchronization information for each node apparatus through the specifying device. Synchronization status information indicative of the transmission of synchronization information is written to the memory block corresponding to the node apparatus for which the transmission of synchronization information has been specified. Synchronization status information indicative of the reception of synchronization information is written to the memory block corresponding to the node apparatus for which the reception of synchronization information has been specified. Consequently, the user can simply and surely specify the transmission/reception of synchronization information for each node according to the indication made by the indicating device, thereby providing the transmission/reception setting as specified by the user.
In carrying out the invention and according to another aspect thereof, there is provided a second communication control apparatus for setting a plurality of node apparatuses including a first node apparatus and a second node apparatus involved in a network to either of a transmitter and a receiver of synchronization information circulated through the network to synchronize the node apparatuses with each other. In the communication control apparatus, a storage device memorizes common master information effective to specify the first node apparatus to a transmitter of synchronization information commonly used throughout the network. A determining device operates based on the memorized common master information for outputting status information effective to determine the second node apparatus to a receiver of the synchronization information transmitted from the first node apparatus. A memory block is provided in correspondence to the second node apparatus to memorize status information of the second node apparatus. A registering device registers the outputted status information into the memory block to set the second node apparatus to a receiver of the synchronization information.
According to the second communication control apparatus, the storage device stores the common master information for specifying the first node apparatus as a transmitter of synchronization information common to the network. The determining device determines, for the second node apparatus, the reception of synchronization information from the first node apparatus on the basis of the common master information stored in the storage device. Synchronization status information indicative of the reception of synchronization signal is written to the memory block according to the determination made by the determining device. Consequently, the reception of synchronization information can be automatically determined on the basis of the common master information, allowing the setting of reception in accordance with the automatic determination.
In carrying out the invention and according to still another aspect thereof, there is provided a third communication control apparatus for setting a plurality of node apparatuses involved in a network to either of a transmitter and a receiver of synchronization information circulated through the network to synchronize the node apparatuses with each other. In the communication control apparatus, a storage device memorizes capability information representing either of an active capability to transmit the synchronization information and a passive capability to receive the synchronization information, possessed by each of the node apparatuses. An indicating device indicates node apparatuses possessing the active capabilities according to the memorized capability information. A specifying device outputs common master information effective to specify one node apparatus among the indicated node apparatuses to a transmitter of synchronization information commonly used throughout the network. A first memory block memorizes the common master information outputted from the specifying device. A determining device operates based on the memorized common master information for outputting status information effective to determine another node apparatus among the plurality of the node apparatuses to a receiver of the synchronization information transmitted from said one node apparatus. A second memory block is provided in correspondence to said another node apparatus to memorize status information of said another node apparatus. A registering device registers the outputted status information into the second memory block to set said another node apparatus to a receiver of the synchronization information.
According to the third communication control apparatus, a node apparatus capable of transmission is indicated by the indicating device on the basis of synchronization capability information stored in the storage device. The user refers to the indication made by the indicating device to specify through the specifying device one node apparatus as a transmitter (a common master) of synchronization information common to the network. The common master information indicative of one node apparatus associated with the specification is stored in the first memory block. The determining device determines, for another node apparatus associated with the specification, the reception of synchronization information from one node apparatus associated with the specification on the basis of the common master information stored in the first memory block. Synchronization status information indicative of the reception of synchronization information is written to the second memory block according to the determination made by the determining device. Consequently, the user can simply specify a desired node apparatus as the common master according to the indication made by the indicating device, thereby the determining device automatically determining the reception of synchronization information in another node apparatus with respect to the specified common master. This permits the setting of transmission/reception in accordance with user specification and automatic determination.
In carrying out the invention and according to yet another aspect thereof, there is provided a fourth communication control apparatus for setting a plurality of node apparatuses including a first node apparatus, a second node apparatus and a third node apparatus involved in a network to either of a transmitter and a receiver of synchronization information circulated through the network to synchronize the node apparatuses with each other. In the communication control apparatus, a memory block memorizes status information effective to specify the first node apparatus to a receiver of the synchronization information transmitted from the second node apparatus. A determining device operates based on the memorized status information for outputting status information effective to determine the third node apparatus to a receiver of the synchronization information transmitted from the second node apparatus. Another memory block is provided in correspondence to the third node apparatus to memorize status information of the third node apparatus. A registering device registers the outputted status information into said another memory block to set the third node apparatus to a receiver of the synchronization information.
According to the fourth communication control apparatus, synchronization status information indicative of the reception of synchronization information from the second node apparatus by the first node apparatus is stored in the memory block. The determining device determines, for the third node apparatus, the reception of synchronization information from the second node apparatus on the basis of the synchronization status information stored in the memory block. Synchronization status information indicative of the reception of synchronization information from the second node apparatus is written to a memory block of the third node apparatus in accordance with the determination made by the determining device. Consequently, the reception of synchronization information can be automatically determined on the basis of the synchronization status information, thereby allowing the setting of reception in accordance with the automatic determination.
In carrying out the invention and according to a different aspect thereof, there is provided a fifth communication control apparatus for setting a plurality of node apparatuses including a first node apparatus and a second node apparatus involved in a network to either of a transmitter and a receiver of synchronization information circulated through the network to synchronize the node apparatuses with each other. In the communication control apparatus, a memory block memorizes active status information effective to specify the first node apparatus to a transmitter of synchronization information. A determining device operates based on the memorized active status information for outputting passive status information effective to determine the second node apparatus to a receiver of the synchronization information transmitted from the first node apparatus. Another memory block is provided in correspondence to the second node apparatus to memorize status information of the second node apparatus. A registering device registers the outputted passive status information into said another memory block to set the second node apparatus to a receiver of the synchronization information.
According to the fifth communication control apparatus, synchronization status information indicative of the transmission of synchronization information from the first node apparatus is stored in the memory block. The determining device determines, for the second node apparatus, the reception of synchronization information from the first node apparatus on the basis of the synchronization status information stored in the memory block. Synchronization status information indicative of the reception of synchronization information from the first node apparatus is written to another memory block corresponding to the second node apparatus in accordance with the determination made by the determining device. Consequently, the reception of synchronization information can be automatically determined on the basis of the synchronization status information, thereby allowing the setting of reception in accordance with the automatic determination.
In carrying out the invention and according to a still different aspect thereof, there is provided a sixth communication control apparatus for setting a plurality of node apparatuses including a first node apparatus and a second node apparatus involved in a network to either of a transmitter and a receiver of synchronization information circulated through the network to synchronize the node apparatuses with each other. In the communication control apparatus, a storage device memorizes capability information representing either of an active capability to transmit the synchronization information and a passive capability to receive the synchronization information, owned by each of the first node apparatus and the second node apparatus. A determining device is operated according to a predetermined rule and according to the active capability and the passive capability owned by the first and second node apparatuses for outputting status information effective to specify either of the first and second node apparatuses to a transmitter or a receiver of the synchronization information. First and second memory blocks are provided in correspondence to the first and second node apparatuses to memorize status information of the corresponding node apparatuses. A registering device registers the status information into the first memory block to set the first node apparatus to a transmitter or a receiver of the synchronization information when the status information is determined for the first node apparatus, and registers the status information into the second memory block to set the second node apparatus to a transmitter or a receiver of the synchronization information when the status information is determined for the second node apparatus.
According to the sixth communication control apparatus, the determining device determines the transmission or reception of synchronization information for each of the first and second node apparatuses on the basis of the synchronization capability information stored in the storage device and in accordance with the predetermined determination rule. Synchronization status information indicative of the transmission or reception of synchronization information is written to the first memory block in accordance with the determination made by the determining device with respect to the first node apparatus. Otherwise, synchronization status information indicative of the transmission or reception of synchronization information is written to the second memory block in accordance with the determination made by the determining device with respect to the second node apparatus. Consequently, the transmission/reception of synchronization information can be automatically determined on the basis of the synchronization status information, thereby allowing the setting of transmission/reception in accordance with the automatic determination.